Variable curve linebar with skewable saws

ABSTRACT

The present invention is the combination of a linebar and saw assembly for sawing cants or logs having various amounts of sweep in order to maximize the yield. The linebar is conformable between a straight line and a line which approximates an arc of a circle. Both ends of the linebar are positioned relative to the saw so that one end is essentially adjacent to the center of the saw. Both ends of the linebar always remain on the line defined by the linebar when it is in straight line position. A tangent to the end of the linebar adjacent to the saw is always parallel to the plane defined by the saw. The saw is skewable about the point of intersection of the end of the linebar with a line drawn from the centerline of and normal to the plane of the saw. A mechanism for bending the linebar and skewing the saw completes the invention. Using this invention the linebar can be configured into an arc which approximates the sweep curvature of a cant or log being sawn. As the linebar is bent the saw is skewed to maintain parallelism with the line of tangency. The invention is particularly well adapted for use in sawmills where space is limited and where there may not be room to use a variable curve linebar which is deflected only at one end. Improvements of lumber recovery to about 20% are achieved by sawing around the curve as compared with processing similar sweepy cants by straight line sawing.

BACKGROUND OF THE INVENTION

The present invention comprises a linebar and saw assembly for sawinglogs or cants having varying amounts of sweep from piece to piece. It isespecially useful for increasing the recovery of saleable lumber fromsweepy cants or logs.

Within a few more years, the last of the old growth timber available forharvesting in the United States will have been cut. Most of the sawmillswhich formerly depended on large old growth logs have already had toconvert the equipment in their mills to that which is suitable forhandling much smaller logs at high throughput volumes. One commoncharacteristic of second growth timber is that the logs usually havevarying amounts of sweep or curvature. The presence of sweep results inyields which are significantly lower than those which are attainablefrom straight logs. This is because much of the curved portion must bemachined off in order to produce cants or lumber having the usualconfiguration of a rectangular parallelepiped.

Most small log sawmills orient the log prior to the primary breakdownsaw so that the greatest curvature is either up or down (horns up orhorns down) rather than side to side. These opening cuts may be eithermade by saws or by chippers which reduce the sides of the log to woodchips suitable for pulping. The result is a cant having parallel faceson two sides. As noted earlier, cants sawn in this fashion tend to haveappreciable sweep. Sweep is here defined to mean the curvature on theconcave edge of the cant when the cant is placed on one of its flatfaces. While occasional instances of extreme sweep occur, in most casessweep is rarely greater than about 100 mm in a cant approximately 5 mlong (about 4 in. in 16 ft.). Most typically, it will be about half ofthis amount.

Man has had to attempt to cope with geometric irregularities in logsever since he began to utilize trees. Thus, it is not unexpected thatthe prior art shows previous attempts to deal with sweepy cants and todevise schemes for improving the yield from cants of this type.

As general background to the present invention, reference can be made toU.S. Pat. Nos. 259,661 to Bowker and 1,263,443 to Lien. Both of theseinventors devised schemes for sawing wooden barrel hoops along a paththat was precisely parallel to the outside surface of the log. This wasdeemed necessary in order to reduce the presence of cross grain whichwould reduce the strength of the hoop. Somewhat more pertinent is GreatBritain Pat. No. 545 of 1852. In this sawing device, a tree was placedon a carriage which could be moved in a circular arc with respect to asaw. The purpose here appears to be to cut complex curved and/or angledships timbers. However, it appears inherent in the invention that cutscould be made parallel to the surface of a curved log.

Japanese Pat. No. 49-7557 shows a device used for "sawing around thecurve" of a cant which contains sweep. The cant is first sawn to produceone good edge parallel to the original surface. After this point,additional boards can be taken off parallel to this surface by manuallysteering the cant as it emerges from the saw.

Swedish Pat. No. 33,098 is a sawing device having feed rolls which canbe canted so that the axes lie at an angle and intersect at a pointcorresponding to the arc of a curve along which a cut is to be made.U.S. Pat. No. b 3,685,556 to VanSickle takes a somewhat differentapproach. This inventor shows a device for use with a shop band saw forcutting predetermined contoured pieces for straight stock to make; e.g.,Christmas tree stands. More conventional approaches are described inU.S. Pat. No. 3,665,984 to Ackerfeldt, U.S. Pat. No. 4,416,312 toOstberg and Swedish Pat. No. 306,415. These, in general, deal withpositioners for optimizing yields from curved cants by straight linesawing. The patent Ackerfeldt is valuable for the background it gives tothis type of approach.

Whle it has been noted that increased yields can be obtained by "sawingaround the curve", until very recently nothing has been done to makethis a practical approach in a modern, high-speed sawmill. The closestexamples can be found in U.S. Pat. Nos. 4,144,782 and 4,219,056 toLindstrom and U.S. Pat. No. 4,373,563 to Kenyon. The earlier of the twoLindstrom patents is of particular interest. In the device described, alog is fed into what is preferably a single band saw along a path whichfollows the curvature of the log. The log lies on a roll case with twopairs of opposing vertical guide rollers upstream from the saw. Theseguide rollers embrace the cant as it is fed into the saw. They aremounted on frames transversely displaceable to the path of the log sothat the log is directed along a curve to which the saw blade istangent. Lindstrom further notes that the bowed boards resulting fromaround-the-curve sawing will generally flatten out when they are kilndried. Kenyon shows a somewhat similar system. However, the cant isoriented by lateral pressure applied only to one side of the cant by aroller located upstream from the point of sawing.

To the present inventor's knowledge, the devices taught by Lindstrom andKenyon have had limited commercial application although their use hasnot become widespread. This may possibly be because they are of limiteduse in a high-speed sawmill which may typically run 10-20 cants perminute through a gang saw.

In two earlier applications commonly assigned with the present one andin which the present applicant is a co-inventor, the applicants havesuccessfully dealt with the problem of maximizing yield from cantshaving significant amounts of sweep. One method utilizes apparatusdisclosed in Ser. No. 793,925, filed Nov. 1, 1985, which is herebyincorporated by reference. This application shows a linebar which can bebent by the sawyer to varying degrees of curvature which will correspondto the curvature of the particular cant being sawn. At a point oppositethe saw arbor a tangent to the linebar always lies parallel to the planeof the saws. A second application, Ser. No. 814,137, filed Dec. 27,1985, which is also herein incorporated by reference, discloses the useof a linebar having a fixed curvature. This curvature is equivalent tothe average sweep found in a large sample of cants being processed bythe sawmill. As is the case with the other linebar, a tangent to thelinebar at a point opposite the projected axis of the saw arbor liesparallel to the plane of the saws.

Both of the above linebars have had a positive effect upon recovery inmills where they can be incorporated. Unfortunately, sometimes the firstof these devices can not be used due to physical limitations foundwithin sawmills. A typical small log sawmill might have a gang sawlinebar 7.3 m (24 ft) in length. For a cant having about 50 mm sweep in4.9 m length (2 in in 16 ft) the infeed end of the linebar must bedeflected about 460 mm (18 in) from the tangent line. Space is notalways available in a sawmill to accommodate a linebar deflection ofthis magnitude. The second device described above gives a majorimprovement over straight line sawing but cannot take full advantage ofthe possible yield increase since it is configured for a cant of"average" sweep.

The present invention is designed to overcome the problems of spacelimitations which would prevent one of the above linebars from beingutilized. In addition, it has other advantages which will now bedescribed.

SUMMARY OF THE INVENTION

The present invention comprises a linebar and saw assembly for sawingcants or logs which have varying amounts of sweep from piece to piece.Sweep is here defined as longitudinal curvature in a cant or log. In agenerally rectangular piece this curvature is normally found along thenarrower face. The invention also comprises a method for sawing logs orcants of this type for increasing lumber recovery.

One element of the invention is at least one saw, which may be either abandsaw or circular saw. most commonly the saw will be a gang saw havinga plurality of circular saws on a common arbor. A second element is anelongated flexible linebar which is conformable at the will of anoperator between a straight line and a line approximating an arc of acircle. This linebar is positioned relative to the saw so that one endis adjacent to the center of the saw. "Center" is here defined as thatcenterline of the saw lying in the plane of the saw and normal to aprojection of the longest dimension of the linebar. Both ends of thelinebar always lie on the line defined by the linebar when it is instraight line position. Bending forces are applied so that only thecentral portion of the linebar is deflected without significant changein the location of either end. This is in contrast to the variable curvelinebar described in application, Ser. No. 814,137, in which one end ofthe linebar is deflected. A tangent drawn along the end of the linebarwhich is adjacent to the saw is always essentially parallel to the planedefined by that saw. The saw itself is skewable at the point ofintersection of the adjacent end of the linebar with a line drawn normalto the plane of the saw from the previously defined centerline. Theother elements of the apparatus include a means of bending the linebarfor controlling its curvature and a skewing means for the saw.

In use, the linebar can be configured into an arc which approximates thesweep curvature of a cant or log being sawn and the saw can be skewed tomaintain parallelism with the line of tangency at the adjacent end ofthe linebar. Using this procedure a log or cant can be guided into thesaw along a path approximating its radius of curvature so that waste isminimized. Recovery of saleable lumber can be as much as 20 percent thatis obtained using straight line sawing.

The saw or saws can be skewed in various ways. Either the entire sawassembly, including frame, arbor, and/or drive can be skewed about thepoint of rotation. Alternatively, in some types of saw construction itis possible to skew only the saw blades using opposed leading edge andtrailing edge saw guides to control the position.

While this is not essential, it is desirable to be able to control thedistance between the linebar and saw. In the case of a gang saw, thedistance between the linebar and the first or "zero" saw would becontrolled. This enables a slab of varying thickness to be removed tofurther minimize waste of saleable lumber.

It is an object of the present invention to provide a linebar and sawcombination in which the linebar has the capability of being adjusted tovarying degrees of curvature and the saw can be skewed to maintain atangent relationship with the end of the linebar.

It is another object to provide a saw in combination with a linebarwhose curvature can be varied to enable a sweepy cant to be sawed aroundthe curve in order to increase recovery and lumber yield.

It is a further object to provide a variable curve linebar and sawcombination which can be installed within the same space occupied bymore conventional equipment.

It is still another object to provide a variable curve linebar which canbe translated toward or away from the saw to control offset.

These and many other objects will become readily apparent to thoseskilled in the art upon reading the following detailed description takenin conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a relatively straight cant which has been cut intolumber by conventional straight-line sawing.

FIG. 2 represents a sweepy cant cut into lumber by straight line sawing.

FIG. 3 illustrates a similar sweepy cant cut into lumber by sawingaround the curve.

FIG. 4 illustrates the path of a given point on an incoming cant as itapproaches and leaves a circular saw during around-the-curve sawing.

FIGS. 5 and 5A illustrate the relationship of saw side clearance to thepresent invention.

FIG. 6 illustrates a method of sawing a sweepy cant for maximum yield bybending one end of the linebar to approximate the curvature of the cant.

FIG. 7 illustrates the method of the present invention of sawing asweepy cant for maximum yield by bending the linebar and skewing thesaws.

FIGS. 8 to 10A show three methods of bending linebars to assume theconfiguration of an arc of a circle.

FIG. 11 illustrates a method of using a splined saw arbor that may bereadily adapted for skewing saws.

FIG. 12 illustrates one method of skewing all the saws in a circular sawgang saw, using a splined arbor.

FIG. 13 illustrates a vertical arbor gang saw and shows a method bywhich a linebar can be bent into a curved configuration while the sawsare simultaneously skewed.

FIG. 14 is similar to FIG. 13 but shows the linebar in curvedconfiguration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The advantages of the present invention will be made readily apparent byreference to FIGS. 1-3. In FIG. 1, a straight cant 2 has just emergedfrom a circular gang saw 4. This consists of a number of identicalcircular saws 6 mounted on an arbor 8. To provide a point of reference,the saw to which the numeral 6 is directed should be considered as thefirst or "zero" saw. Cant 2 has been cut into a number of boards 10 withedge trimmings 12, 14, comprising waste taken from each edge of thecant. Note that four useful pieces of lumber 10 were obtained.

In contrast, FIG. 2 shows a sweepy cant 16 which has just been processedin a similar manner through the same set of gang saws 4. Cants 2 andcants 16 are of similar surface area. Here edge trimmings 17, 18 wereremoved but only three useful pieces of lumber 10 were obtained.

FIG. 3 shows cant 16 as it could be sawed around the curve. In thiscase, the cant is presented to the saws along a circular path with aradius R. Edge trimmings 19 and 20 generally follow concentric linesparallel to the respective adjacent surfaces. Here, the difference isthat four usable pieces of lumber 10 were again obtained. While theseare somewhat bowed as they leave the saw, experience has shown that theywill normally flatten into a straight configuration during subsequentsawmilling operations, especially when kiln dried.

FIGS. 4-5A illustrate one of the limitations to the minimum radius ofcurvature of sawing. This is in general determined by the available sideclearance of the saw. FIG. 4 shows the path of a point on a cant movinginto the saw along a circular path 21. Note that this circle is tangentto saw blade 6 at the location of arbor 8. Ideally, one would expect thesame point to leave the saw along a similar circular path 22. This isfrequently the case when a roll-type conveyor system is used. However,as the lumber leaves the saw, it attains a considerable degree offlexibility not present in the cant entering the saw and it is free todeviate from the "ideal" path 22. In fact, when a slat bed conveyor isused, the exiting lumber will normally assume a nearly straight linepath as shown at 24. As a practical consideration, lumber can be sawnwith somewhat more sweep than side clearances would seem to dictate.Some saw plate rubbing does not seem detrimental.

FIG. 5A shows a typical circular saw construction in which the saw plate6 has swaged or inserted cutting elements 7. These elements describe apath wider than the saw plate itself and cut a kerf K with remainingside clearance s required to prevent frictional rubbing between thematerial being cut and the side of the saw plate. The permissible radiusof curvature R is that as shown in FIG. 5 which will not result inrubbing of cant 16 against the side of the saw plate. It is desirablethat some minimum clearance should be maintained at all times.

While there is great variability, the plate thickness of circle saw gangsaws will generally vary between 2.4 and 3.4 mm (0.095 to 0.135 in).Side clearance is typically in the 0.25 to 1.0 mm range (0.010 to 0.040in), most typically about 0.4 to 0.5 mm (0.015 to 0.020 in). This isadequate side clearance to accommodate cants fed along a circular pathhaving a radius of approximately 50 m or greater. This radiuscorresponds to cants having sweep of approximately 60 mm in a 5 m lengthor about 3 in. in 16 ft. However, a number of factors will affect theallowable curvature including cant thickness and saw configuration.Decreasing saw diameter also allows curves of shorter radius to be cut.It is believed to be entirely practical to saw around a curve having aradius as short as 30 m. This corresponds to a cant having about 100 mmsweep in 5 m of length or 4 in in 16 ft of length.

The following table shows the radius of curvature for cants of varyinglengths and sweep distances, where sweep distance is the height of thearc defining the sweep. These values can be readily calculated forlengths or sweeps not shown on the table using the formula R=(L² +4h²/8h) where L is the length of the cant and h is the sweep distance.

                  TABLE 1                                                         ______________________________________                                        Radius of Curvature in Meters vs. Sweep for Various Cant Lengths                        Sweep Distance (h), mm                                              Length (L), m.sup.(1)                                                                     20        40     60     80   100                                  ______________________________________                                        2.5         39.1      19.6   13.1    9.8  7.8                                 3.5         76.6      38.3   25.6   19.2 15.3                                 5           156.3     78.2   52.1   39.1 31.3                                 ______________________________________                                    

FIG. 6 illustrates sawing a curved cant using the linebar described inour earlier application, Ser. No. 793,925. Here the linebar 30 has beenbent to a curved position from its normal straight position 30' toapproximate the curvature of a sweepy cant 32. Linebar 30 has a totallength of 7.3 m (24 ft). Cant 32 is 4.9 m (16 ft) with a sweep of 51 mm(2 in). The cant is being fed into a gang saw assembly 34 mounted onarbor 35. Note that a tangent to the linebar at the saw location isessentially parallel to the planes defined by the saws. In the presentcase it is necessary to deflect the infeed end of the linebar about 460mm (18 in).

FIG. 7 shows a cant and linebar of similar configurations to those shownin FIG. 6. Here only the center portion of the linebar is deflectedwhile the ends both remain along the line defined by the linebar when itis in straight line position. However, in the present case, the saws arealso skewed 3.6° to maintain parallelism of the saws with a tangent tothe end of the linebar adjacent the saws. In the present case the centerof the linebar need be deflected only 114 mm (41/2 in). It isimmediately evident that this is only one-fourth of the deflection ofthe linebar deflection required using the arrangement of FIG. 6. In manycases the infeed roll case to the saws is not of sufficient size, nor isspace otherwise available, to accommodate a linebar having the largedeflection shown in FIG. 6. This is generally not the case for anarrangement as shown in FIG. 7 where linebar deflection is relativelyminor.

FIGS. 8 to 10 show three different ways in which linebars can be bent toassume a configuration which is generally that of an arc of a circle.The saw adjacent end of linebar 40 is permanently fixed at 41, whereasthe opposite end 42 must be allowed to translate slightly to accommodatefor bending. This accommodation is provided by slotted anchor block 44.In FIG. 8 linebar 40 is bent to its curved configuration by forcesapplied near each end. In FIG. 9 the forces are applied more uniformlyalong the entire length of the linebar. In both FIGS. 8 and 9 thelinebar may be of uniform thickness from end to end. In FIG. 10 only asingle bending force is applied at the center of linebar 46. Thislinebar has varying thickness, being thicker at the center and thhinnerat each end. Gang saws 37 can be appropriately skewed so that aprojection of the longitudinal axis of the arbor is normal to a tangentto the linebar at anchor point 41.

FIG. 10A is similar to FIG. 10. However, in this case instead of acircular gang saw a single skewable band saw 39 is pictured. Theprinciples of the invention are equally applicable whether a single sawor a bank of parallel saws are used.

FIGS. 11 and 12 illustrate a method of skewing saws which does notrequire moving the saw frame or saw arbor. In this case the saws aremounted on a Retec spline. This is described in Thrasher, U.S. Pat. No.3,516,460. The splines are available from Retec, Inc., Ukiah, Calif.,while the saws are available from several manufacturers. In this casethe saws have no collar where they are mounted on the arbor and there isenough flexibility so that they can be skewed up to about 5° using onlythe saw guides. Here a saw of this type 48 having a leading edge 49 andtrailing edge 50 is mounted on a splined arbor 52. The infeed or leadingedge of the saw 49 is held between guides 54, 56 while the opposite edgeis held between similar guides 58, 60. A number of different types ofsaw guides are available for this function. Suitable guides aredescribed in Fairfield, Jr., et al, U.S. Pat. No. 3,674,065. Guides ofthis type are readily available from a number of vendors and form nopart of the present invention.

FIG. 12 shows a circular gang saw using a splined arbor in which theguides are connected together to serve a saw skewing function inaddition to their usual function of stabilizing the saw blade. At theinfeed side of the saws the blades 48 are embraced between opposedguides 54, 56. These are in turn ganged together to form an infeed guideassembly 62 which is tied to a position control rod 64. The guideposition is ultimately controlled by a fluid cylinder 66. The downstreamguide assembly 68 is similarly constructed with a series of opposed sawguides 58, 60 being ganged to a position control rod 70 whose locationis controlled by fluid cylinder 72.

Either one or both of the guide assemblies may be moved for skewing thesaws. If only one guide assembly is moved for skewing it will normallybe the rear assembly 68. In this case the front assembly 62 is in fixedposition and it is not necessary to have control cylinder 66.Preferably, both guide assemblies will be movable and they will be movedin opposite directions to accomplish the required amount of skewing.Skewing can be controlled either by direct fluid or mechanical linkageto a linebar or by using electronic control, such as a programmablecontroller which senses linebar position and adjusts the amount ofskewing accordingly.

FIGS. 13 and 14 show a similar system employing more conventional gangsaws. Here the combination of skewable saw with variable curve linebaris generally shown at 78. In the present case a vertical gang saw isrepresented but a very similar arrangement could be employed for ahorizontal gang. The saws and linebar are mounted on a base or floormember 80. In the present case the entire saw frame 82 is skewable. Thisis shown in combination with linebar 84. The saw frame contains avertical gang saw 86 with saws 88, 89. Saw 89 is identical to the othersbut is generally designated the zero saw. The saws are mountedconventionally on an arbor 90. The entire saw assembly is held between arear mount 92 and an equivalent front mount, not shown, on which arelocated trunnions 94. Linebar 84 is connected at its saw adjacent end toa subframe member 96. This in turn is connected to a pair of bell cranks97 which control offset adjustment or distance between the linebar andzero saw. The bell cranks are pivoted at 98 to saw frame 82 and areconnected at their far end to a first offset adjustment cylinder 100. Atthe other end of the linebar there is a clevis 102 which is pinned toone end of link 104. The other end of link 104 is pinned to a bell crank106, similar to those adjacent to the saw. This bell crank is pivoted at108 to an extension of main frame 80. A second offset adjustmentcylinder 109 acts in concert with cylinder 100 so that linebar 84 isalways moved in parallel fashion. The linebar is bent and the saws areskewed simultaneously to the action of skewing cylinder 110 which isattached to an extension 113 of saw frame 82. The opposite end ofskewing cylinder 110 is anchored to the base member at extension 114.Shortening the piston rod of cylinder 110 will simultaneously cause thelinebar to be bent and the saws to be skewed while maintaining theparallel relationship between the tangent at the saw adjacent end of thelinebar and the plane containing the saws.

Normally it is never necessary to skew the saws more than about 5° abouttheir point of rotation. This amount of skew can normally be readilyaccommodated by conventional belt drive mechanisms for the saws.

Having thus disclosed the best modes known to the inventor of practicinghis invention, it will be evident to those skilled in the art that manydepartures can be made from the examples described without departingfrom the spirit of the invention. The invention is thus not to belimited to the details disclosed within the description but is to beaccorded the full scope of the claims so as to embrace any and allequivalent devices, apparatus and methods.

What is claimed is:
 1. In combination, a linebar and saw assembly forsawing cants or logs having varying amounts of sweep from piece to piecewhich comprises:at least one saw; an elongated flexible linebar meansconformable between a straight line and a line approximating an arc of acircle, said linebar means being positioned relative to the saw so thatone end is essentially adjacent to that centerline of the saw lying inthe plane of the saw and normal to a projection of the longest dimensionof the linebar, both ends of the linebar means always lying on the linedefined by said linebar means when in straight line position, a tangentto the end of the linebar means adjacent the saw always beingessentially parallel to the plane defined by saw saw; said saw beingskewable essentially about the point of intersection of the end of thelinebar means adjacent the saw with a line drawn normal to the plane ofthe saw from said centerline; bending means for controlling thecurvature of the linebar; and skewing means for the saw, whereby saidlinebar means can be configured into an arc which approximates the sweepcurvature of a cant or log being sawn and said saw can be skewed tomaintain parallelism with the line of tangency of the linebar adjacentsaid saw so that a cant can be guided into the saw along a pathapproximating its radius of curvature.
 2. The linebar and sawcombination of claim 1 in which the saw is a band saw.
 3. The linebarand saw combination of claim 1 in which the saw is a circular sawmounted on an arbor, said saw having a leading edge where the cant orlog first contacts the saw and a trailing edge where the cant or logleaves the saw.
 4. The linebar and saw combination of claim 3 in whichthe saw is a circular gang saw comprising a bank of spaced apartparallel circular saws mounted on the arbor, said saws having leadingedges where the cant or log first contacts the saws and trailing edgeswhere the cant or log leaves the saws.
 5. The linebar and sawcombination of claim 3 in which both arbor and saw are skewed.
 6. Thelinebar and saw combination of claim 3 in which the arbor is splined andonly the saw is skewed.
 7. The linebar and saw combination of claim 4 inwhich both arbor and saws are skewed.
 8. The linebar and saw combinationof claim 4 in which only the saws are skewed.
 9. The linebar and sawcombination of claim 6 including opposed saw guide pairs adjacent theleading and trailing edges of the saw, one of said guide pairs beingfixed and the other being translatable a limited distance to skew thesaws.
 10. The linebar and saw combination of claim 9 in which theleading edge guide pair is fixed and the trailing edge guide pair istranslatable.
 11. The linebar and saw combination of claim 8 includingopposed saw guide pairs adjacent the leading and trailing edges of thesaws, one of said guide pairs being fixed and the other beingtranslatable a limited distance to skew the saws.
 12. The linebar andsaw combination of claim 11 in which the leading edge guide pair isfixed and the trailing guide pair is translatable.
 13. The linebar andsaw combination of claim 6 in which both guide pairs are translatable alimited ddistance in opposite directions to skew the saws.
 14. Thelinebar and saw combination of claim 8 in which both guide pairs aretranslatable a limited distance in opposite directions to skew the saws.15. The linebar and saw combination of claim 1 including translatingmeans for moving the linebar toward or away from the saw to control thedistance between them.
 16. The linebar and saw combination of claim 4including translating means for moving the linebar toward or away fromthe saws to control the distance between said linebar and the sawnearest the linebar.
 17. A method of sawing cants or logs having varyingamounts of sweep from piece to piece which comprises:providing at leastone saw; further providing an elongated flexible linebar meansconformable between a straight line and a line approximating an arc of acircle; said linebar means being positioned relative to the saw so thatone end is essentially adjacent to that centerline of the saw lying inthe plane of the saw and normal to a projection of the longest dimensionof the linebar, both ends of the linebar means always lying on the linedefined by said linebar means when in straight line position, a tangentto the end of the linebar means adjacent the saw always beingessentially parallel to he plane defined by said saw; said saw beingskewable essentially about the point of intersection of the end of thelinebar means adjacent the saw with a line drawn normal to the plane ofthe saw from said centerline; bending the linebar to conform itscurvature to the sweep curvature of the cant or log; and skewing the sawto maintain parallelism with the line of tangency of the linebaradjacent said saw so that the cant is guided into the saw along a pathapproximating its radius of curvature.
 18. The method of claim 17 inwhich the saw comprises a circular saw mounted on an arbor.
 19. Themethod of claim 18 in which the saw is a circular gang saw comprising abank of parallel spaced apart circular saws mounted on the arbor. 20.The method of claim 19 which includes skewing both the arbor and thesaws.
 21. The method of claim 19 in which the arbor is splined and whichincludes skewing only the saws without skewing the arbor.